Question

Two similar cylinders have heights 6 inches and 15 inches.

What is the ratio of their surface areas?

4 : 25
8 : 25
9 : 10
9 : 25

Answer 1

If two figures have heights of x and y, then the ratio of the heights is x:y

This in turn means that the ratio of the surface areas is x^2:y^2

So in this case, x = 6 and y = 15, which means that the ratio of the surface areas is 6^2:15^2 ---> 36:225 ---> 4:25


So the answer is choice A

Answer 2

Thanks so much, you made it real easy to understand!

Answer 3

You're welcome. I'm glad it's making sense.